Safe and durable coffee roasting at Leister

Leister offers a broad product portfolio for industrial hot air applications.

Leister Technologies, a Swiss multinational company active in the design and construction of air heating solutions in the process industry, presents a new technology for coffee roasting.

by Marco Guerra

Leister is probably not the first company you think of when it comes to coffee. In fact, the brand has recently seen its reputation increase among roasting machine manufacturers, with a growing number of companies enthusiastic about the results obtained by applying hot air technology to the roasting process of aromatic beans. Let us find out what benefits the use of Leister solutions provides for this particular segment of the food industry.


By far the most widely used method to date for roasting coffee, an indispensable process for transforming the astringent green berries into fragrant beans intended to create intoxicating infusions, is to introduce the berries into rotating barrels heated by gas-fired flames.

The method is consolidated and depends largely on the skill of the operator, who carefully adjusts the mixture and the flow of the fuel to obtain a constant temperature suitable for the desired degree of roasting. Of course, this process is affected by all limits from a safety point of view, which are the presence of flammable gases, which in certain environments are subject to restrictions or explicitly prohibited.


The biggest advantage perceived by those who use gas heating is the speed with which the coffee reaches the desired temperature and the ability to keep it constant to guarantee an always identical aroma: once the consumer has identified his favorite coffee, he does not. unexpected variations.

The need for a process that is always repeatable and equal to itself tends to create a certain uncertainty towards innovations, which are perceived as a harbinger of possible deviations from the standards of perfection that have been so painstakingly achieved.

The good news for the proudly preserved tradition is that the same repeatability and reliability results can be achieved with air heating, as demonstrated by a recent experiment conducted by Probat, a German multinational, world leader in manufacturing machinery and systems for industry. food, especially specializing in the coffee sector.

Leister’s range of hot air heaters for roasting coffee includes solutions for machines of all sizes.


For over 150 years, spanning four generations, Probat has been supplying rusting machines to leading companies in the sector around the world.

Probat’s machines roast coffee to perfection, regardless of size: they are actually segmented by capacity, from large industrial machines to small roasteries that handle 5 kg of coffee at a time, up to small solutions for laboratories with a capacity of only 200 g, where berries are tested Before purchasing, new roasting methods are tested and innovative blends are created under the supervision of experts in the segment.

Probat compared the two heat sources, gas-fired flames and hot air, and found that both could provide an excellent match to the ideal curve for temperature variation over time, determined by the roaster, to get exactly the type of taste desired by the consumer. Once this essential requirement was met, it was possible to compare the technologies from other points of view.


Probat was able to verify that hot air offers significant advantages over gas heaters, with the same repeatability and consistency in the process, significant conditions in the roasting segment.

The first and most obvious advantage concerns safety: the absence of open flames makes the use of air heaters more reassuring in all circumstances, but in some situations they are the only acceptable option. This is the case, for example, with small coffee roasteries that are open to the public, where the presence of flammable gases is not permitted under current safety regulations; the same applies to other contexts, such as cruise ships and many shopping malls.

The electric heaters, in addition to being able to interrupt the process very quickly in an emergency, allow to provide very precise temperature adjustments also by intervening remotely, removing combustion residues during the process and enabling a much more precise adjustment of the aroma.

The hot air roasting process, compared to the use of gas heaters, also generates a much lower amount of carbon dioxide, hydrocarbons and sulfur oxide, substances that can change the organoleptic properties of the roasted beans, and are unhealthy. Product quality is improved, as is consumer satisfaction.

Another strength of electric heaters is the ability to integrate into existing systems, even if they were originally designed for gas heating; with small costs, the need to install or update the safety devices required for gas heaters is eliminated and the downtime for related maintenance is reduced.

Leister interval heater.


In search of a heating system that did not have the disadvantages of gas, Probat turned to Leister, knowing that they would find a reliable partner, with over 70 years of experience in designing and implementing effective solutions for the industry.

Probat has decided to introduce air heating in its P05 model, intended for small roasters. With a capacity of 5 kg, this model was designed with a 14 kW gas heater; it was possible to replace it with a 17 kW air heating system using the LE 10000 DF-C heater.

The electric air heater LE 10000 DF-C is one of Leister’s products designed for integration in so-called “clean rooms”, where hygienic conditions that meet strict requirements are required, such as in the medicine, pharmaceutical and of course the food sector.

LE 10000 DF-C has been developed on the basis of the latest standards for clean production, defined by the European Hygienic Engineering & Design Group.

Made entirely of non-toxic materials, the LE 10000 DF-C minimizes particulate emissions thanks to the choice of materials used and its design.

LE 10000 DF-C installation is quick and easy; in addition to the heater, it was possible to install sensors for automatic temperature control. Accuracy and flexibility are completely comparable to the gas heater, as is the quality of the finished product; The efficiency of the process is higher, with benefits for consumption and the environment.

The P05 model is commercially the most relevant, but not the only, among Probat machines that integrate Leister technology. Even the small laboratory machine Probat, with a capacity of only 200 grams, roasts the coffee with the heat from the proven Mistral 6 system.

With a weight of only 1.5 kg, the autonomous heater Mistral 6 System requires very little maintenance thanks to the brushless motor.

Easy to install, the Mistral 6 System is equipped with an automatic cooling function. The system interface allows you to control both the heat and the outgoing air from the outside: the convenient display provides status information and enables direct programming.

With a weight of only 1.5 kg, the autonomous heater Mistral 6 System requires very little maintenance thanks to the brushless motor.


Leister’s range of hot air heaters for coffee roasting includes solutions for machines of all sizes: from freestanding heaters with a built-in fan for the most compact systems, to heaters and fan combinations for the larger sizes.

For small laboratory devices with a capacity of less than 500 grams, the ideal, as we have seen, is Mistral; In addition to the previously mentioned 6 System version, Mistral is also available in the Premium 2, 4 and 6 versions, where temperature and air flow are controlled in a very simple way with the help of a potentiometer.

To roast up to 1 kg of beans, heaters such as Hotwind or Vulcan can be used. Hotwind, Mistral’s big brother, is characterized by its more than double capacity to generate hot air (maximum flow 900 l / min); the power of the heating element starting from 2,300 W in the simpler model and reaching 5,400 W in the more efficient model. Hotwind is also available in the two Premium and System versions.

Vulcan provides up to 11 kW of heat output in a compact, robust and easy to integrate into industrial processes.

Small and medium-sized roasteries with a need to roast batches from 1 to 12 kg can use a heater – from the LHS series, available in a power range from 550 W up to 40 kW, up to the used LE 1000 DF-C model that we have seen for Probat P05 – connected to a fan such as Mono, Robust or Airpack.

The small size of the Mono 6 System fan should not be misleading: it weighs only 1 kg but has an air flow of up to 600 l / min, adjustable via the e-Drive control unit or external interface. The brushless motor eliminates the need for maintenance and allows continuous operation.

Robust is a compact fan: with only 8 kg weight, it has an air flow of 1,200 l / min. It has a sound insulation system that makes it very quiet, it is robust and can be used in all situations, even continuously and in difficult environmental conditions.

For larger systems, Airpack is certainly suitable, it can transport large amounts of air at high pressure. Powerful (2,200 W) and high-performance (3,900 l / min), it can also power more than one heater at a time. Various accessories are also available for the Airpack: hoses, adapters and nozzles.

Leister fans and heaters are a winning combination for recycling process hot air: a way to save energy and reduce emissions.


The set of positive features of hot air systems – high and constant quality, easy handling and control, fewer residues, compatibility with recipes developed for gas heaters, greater safety, reduced consumption and lower emissions – make Leister’s solutions for frying especially appreciated by operators who pay more attention to the environment , as well as of course on the quality of the coffee.

This is why many manufacturers of roasting equipment follow Probat’s example and use Leister’s solutions for faultless roasting. © TECNeLaB

Roasting solutions from Leister are especially popular among environmentally conscious operators.


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